link: extract keg-only check into a helper method

Library/Homebrew/cmd/link.rb

@@ -19,9 +19,11 @@ module Homebrew extend self
         opoo "Already linked: #{keg}"
         puts "To relink: brew unlink #{keg.fname} && brew link #{keg.fname}"
         next
-      end
-
-      if mode.dry_run and mode.overwrite
+      elsif keg_only?(keg.fname) && !ARGV.force?
+        opoo "#{keg.fname} is keg-only and must be linked with --force"
+        puts "Note that doing so can interfere with building software."
+        next
+      elsif mode.dry_run && mode.overwrite
         print "Would remove:\n" do
           keg.link(mode)
         end
@@ -35,16 +37,6 @@ module Homebrew extend self
         next
       end
 
-      begin
-        f = Formula.factory(keg.fname)
-        if f.keg_only? and not ARGV.force?
-          opoo "#{keg.fname} is keg-only and must be linked with --force"
-          puts "Note that doing so can interfere with building software."
-          next
-        end
-      rescue FormulaUnavailableError
-      end
-
       keg.lock do
         print "Linking #{keg}... " do
           puts "#{keg.link(mode)} symlinks created"
@@ -55,6 +47,12 @@ module Homebrew extend self
 
   private
 
+  def keg_only?(name)
+    Formula.factory(name).keg_only?
+  rescue FormulaUnavailableError
+    false
+  end
+
   # Allows us to ensure a puts happens before the block exits so that if say,
   # an exception is thrown, its output starts on a new line.
   def print str, &block